A photographic roll film generally called a Brownie film is a longitudinal film which has a relatively large width and is wound around a cylinder core (generally referred to a "spool") utilizing a light-shielding backing paper or leader paper. The photographic roll film of the Brownie type is generally not encased in a magazine (or patrone), which is in contrast to a photographic film of 135 type (which is generally referred to as "35 mm film") which is encased in a magazine or patrone. Brownie films are classified into two types, that is, a relatively short roll film named "120 size film" and a relatively long roll film named "220 size film". In the 120 size film, the photographic roll film is placed on and supported by a shielding paper (backing paper). In the 220 size film, one leading paper having a light shielding property is attached to each end of the photographic roll film under the condition that a certain overlapping area is formed between the roll film and the leader paper. The backing paper and leading paper are joined to the photographic roll film using a separately prepared jointing tape.
Brownie film is advantageous for producing a photographic image of a larger size, and recently a demand for Brownie film has gradually increased. However, complicated procedures for installing a photographic roll film of Brownie type form a barrier to the spread of use of Brownie films. In contrast, a widely employed photographic image-forming system using a 35 mm film and a camera for the 35 mm film utilizes a magazine which has on its outer surface an electrically detectable code which transmits information on the photographic film to a camera when the film is installed into the camera. The information is for the type of photographic film such as monochrome, negative color, or positive color, the photographic sensitivity of the film, the length of the film, etc. When the photographic film is installed into a camera, an electric code detector device equipped with the camera works to read the information of the installed photographic film from the code on the surface of the magazine and automatically sets the operational conditions of the camera according to the information contained in the code. Therefore, there is no need for setting complicated operational conditions in the camera for those who want to take photographic pictures. For a photographic image producing system using Brownie films and a camera therefor, no magazine system is provided. Accordingly, those who want to take photographic pictures using Brownie film themselves should set all information relating to the photographic film in the camera.
In order to obviate the complicated procedures in the use of Brownie type films, the present inventors have already invented a new system which comprises a photographic roll film having a jointing tape on which a bar code containing information for the photographic film is printed and a camera equipped with an optical bar code detector device. The bar code detector automatically reads the bar code and transmit the information to the camera for automatically setting the operational conditions in the camera.
The above-mentioned new photographic system utilizing a Brownie film having a jointing tape on which a bar code is printed is very advantageous because a photographer is not required to input by himself into the camera the information relative to the photographic film by the complicated procedures. Further, the new system is advantageous from the point of view that erroneous input is avoided.
In the course of improvement studies for the new photographic system, the inventors have noted that reading errors sometimes happen. In more detail, in the new photographic system comprising a photographic roll film using a jointing tape on which a bar code is printed and a camera equipped with an optical bar code detector device, the bar code detector device sometimes fails to read the information from the bar code in the course of repeated procedures.
When such reading errors happen, a photographer can manually input the information relating to the roll film into the camera. However, as described above, the manual input is a complicated and troublesome procedure. Therefore, the reading error should be avoided.
Accordingly, the inventors have further continued to study the cause of the reading error and the measures for obviating the reading error. As a result, the inventor have found that the reading error is caused by deformation of the jointing tape and the accompanying deformation of the bar code. In more detail, the jointing tape is fixed on the edge of the roll film to cover the end portion of the roll film and the backing paper or leader paper. The photographic roll film generally has a thickness of approximately 100 .mu.m. Therefore, the photographic roll film and the backing paper or leader paper form certain differences in level at the edge line of the roll film. Accordingly, the jointing tape placed on the edge line of the roll film is liable to show deformation in the thickness direction. Moreover, since the Brownie film is tightly wound around the spool, the deformation of the jointing tape is amplified in the course of storage of the film.
The optical bar code detector (i.e., bar code reader) functions to apply a detecting light on the surface of the bar code and detect a pattern of scattered light reflection from the bar code. The detected pattern is then processed in the detector to output the data having been contained in the bar code.
According to the studies of the inventors, the deformation of the jointing tape is apt to decrease the amount of the scattered light reflection which should be collected by the detector for analyzing the operational data or to give a modified bar code pattern to the bar code detector. These problems sometimes cause the detection errors.